Substantially all of today's automotive cooling systems utilize a surge bottle or reservoir connected to an overflow conduit from the radiator. The surge tank or reservoir provides for storage of a quantity of coolant required to automatically replace any coolant lost during operation of the system, and as the coolant is heated, it expands in volume, with the expanded fluid being accommodated in the reservoir or surge bottle. As some vehicles, specifically heavy duty trucks or buses, use a pressurized bottle, the bottle is subjected to a positive system pressure, and is formed of a metal or heavy plastic. The present invention relates to an arrangement to depressurize the surge bottle so that a lighter weight material can be utilized in forming the bottle for either car or truck applications.
The present invention comprehends the provision of a lightweight material depressurized surge bottle or reservoir in a coolant system for an automotive vehicle engine. To maintain the reservoir or surge bottle at atmospheric pressure, a venturi is located in a by-pass for the coolant pump to recirculate a small portion of the coolant flow from the pump outlet to the pump inlet. The venturi throat is connected with the surge bottle through a make-up line.
The present invention also comprehends the provision of an automotive coolant system which provides a controlled coolant flow system through a depressurized surge bottle. Thus, when the coolant system pressure increases to a predetermined value due to coolant expansion, the coolant will flow through the overflow tube from the radiator to the surge bottle, and this amount of coolant plus any amount necessary to fill the system will be drawn through the make-up line due to the low pressure created in the venturi throat.
The present invention further comprehends the provision of an automotive coolant system having a continuous controlled coolant flow system, wherein a controlled capillary tube may replace or be used simultaneously with the overflow tube from the radiator, maintained at a positive pressure, to the surge bottle at atmospheric pressure. This capillary tube is designed to have a pressure drop substantially equal to the pressure differential between the pressurized coolant system and atmosphere. This will provide an effective deaeration of the cooling system wherein gas leakage is present through the cylinder head gasket. The entrapped gas is continuously moved through the system to the reservoir where the gas can escape.
The present invention also comprehends the provision of an automotive cooling system wherein a continuous controlled coolant flow through the reservoir permits the placement of a sensor or corrosion inhibitor package or membrane for a package in the reservoir to be in contact with coolant flow at all times. When the inhibitor concentration in the coolant decreases, the sensor will generate a signal or the membrane or package will corrode and break open to release additional inhibitor into the coolant system.
The present invention also provides an automotive coolant system having a venturi in a recirculation conduit around the coolant pump and connected through a make-up line to the surge bottle at atmospheric pressure with a one-way or check valve located in the make-up line to prevent back flow to the surge bottle and maintain a positive pressure in the coolant system.
Further objects are to provide a construction of maximum simplicity, efficiency, economy and ease of assembly and operation, and such further objects, advantages and capabilities as will later more fully appear and are inherently possessed thereby.